Sharing documents or files securely currently involves complex and tedious procedures that are often costly and error-prone. There are several approaches available for sharing documents, except none offer an adequate means for easily sharing documents in a secure manner. For instance, one approach involves sending documents as secure electronic mail (“e-mail”) message attachments. This approach involves a great deal of administrative overhead, such as requiring operators to apply for trusted certificates and to exchange the certificates and keys before they can send the messages. Thus, much effort is expended in simply setting up the security protocols instead of towards the goal of sharing files. Further, both parties must have access to their e-mail server, which may not always be possible in real-time. Also, the delays and bandwidth requirements involved in transporting the documents may be unacceptable due to network congestion. For instance, some recipients may receive their documents too late because their e-mail servers were slow.
Additionally, this approach is not effective in a collaborative environment. For instance, if one member of a collaborative group desires making a change to a shared document, they need to send the revised copy to all of the group members, who then must save the copy. This may cause a great deal of confusion since group members may have multiple versions of the same document at one time. One could envision an e-mail in-box that sorts and displays received e-mail messages based upon a time of receipt. If the e-mail messages were transmitted at varying speeds, then it would be difficult to determine whether the displayed order of received messages accurately reflects the order they were originally sent in.
Another approach uses a central server, such as an FTP server, to allow clients to access and securely share documents stored on the server. But these servers can be single points of failure, and often require a high degree of administrative overhead to setup the security protocols. Worse yet, central servers may not even be available in ad-hoc distributed network environments. With the advent of devices and services that can communicate in a fluid, ad-hoc manner, a central server scheme is inadequate for sharing documents securely.